<template>
  <div :class="classes">
    <div class="haloe-date-picker-cells-header">
      <span v-for="day in headerDays" :key="day">
        {{ day }}
      </span>
    </div>
    <span
      v-for="(cell, i) in cells"
      :key="String(cell.date) + i"
      :class="getCellCls(cell)"
      @click="handleClick(cell, $event)"
      @mouseenter="handleMouseMove(cell)"
    >
      <em>{{ cell.desc }}</em>
    </span>
  </div>
</template>
<script>
import { clearHours, isInRange } from '../util'
import Locale from '../../../mixins/locale'
import jsCalendar from 'js-calendar'

import mixin from './mixin'
import prefixCls from './prefixCls'

export default {
  mixins: [Locale, mixin],

  props: {
    /* more props in mixin */
    showWeekNumbers: {
      type: Boolean,
      default: false,
    },
  },
  computed: {
    classes() {
      return [
        `${prefixCls}`,
        {
          [`${prefixCls}-show-week-numbers`]: this.showWeekNumbers,
        },
      ]
    },
    calendar() {
      const weekStartDay = Number(this.t('i.datepicker.weekStartDay'))
      return new jsCalendar.Generator({
        onlyDays: !this.showWeekNumbers,
        weekStart: weekStartDay,
      })
    },
    headerDays() {
      const weekStartDay = Number(this.t('i.datepicker.weekStartDay'))
      const translatedDays = [
        'sun',
        'mon',
        'tue',
        'wed',
        'thu',
        'fri',
        'sat',
      ].map((item) => {
        return this.t('i.datepicker.weeks.' + item)
      })
      const weekDays = translatedDays
        .splice(weekStartDay, 7 - weekStartDay)
        .concat(translatedDays.splice(0, weekStartDay))
      return this.showWeekNumbers ? [''].concat(weekDays) : weekDays
    },
    cells() {
      const tableYear = this.tableDate.getFullYear()
      const tableMonth = this.tableDate.getMonth()
      const today = clearHours(new Date()) // timestamp of today
      const selectedDays = this.dates.filter(Boolean).map(clearHours) // timestamp of selected days
      const [minDay, maxDay] = this.dates.map(clearHours)
      const rangeStart =
        this.rangeState.from && clearHours(this.rangeState.from)
      const rangeEnd = this.rangeState.to && clearHours(this.rangeState.to)

      const isRange = this.selectionMode === 'range'
      const disabledTestFn =
        typeof this.disabledDate === 'function' && this.disabledDate

      return this.calendar(tableYear, tableMonth, (cell) => {
        // normalize date offset from the dates provided by jsCalendar
        // Comment out this code to fix daylight saving time bug
        // https://www.cnblogs.com/hamsterPP/p/5415472.html
        if (cell.date instanceof Date)
          cell.date.setTime(
            cell.date.getTime() +
              cell.date.getTimezoneOffset() * 60000 +
              480 * 60 * 1000
          )

        const time = cell.date && clearHours(cell.date)
        const dateIsInCurrentMonth =
          cell.date && tableMonth === cell.date.getMonth()
        return {
          ...cell,
          type: time === today ? 'today' : cell.type,
          selected: dateIsInCurrentMonth && selectedDays.includes(time),
          disabled:
            cell.date && disabledTestFn && disabledTestFn(new Date(time)),
          range:
            dateIsInCurrentMonth &&
            isRange &&
            isInRange(time, rangeStart, rangeEnd),
          start: dateIsInCurrentMonth && isRange && time === minDay,
          end: dateIsInCurrentMonth && isRange && time === maxDay,
        }
      }).cells.slice(this.showWeekNumbers ? 8 : 0)
    },
  },
  methods: {
    getCellCls(cell) {
      return [
        `${prefixCls}-cell`,
        {
          [`${prefixCls}-cell-selected`]:
            cell.selected || cell.start || cell.end,
          [`${prefixCls}-cell-disabled`]: cell.disabled,
          [`${prefixCls}-cell-today`]: cell.type === 'today',
          [`${prefixCls}-cell-prev-month`]: cell.type === 'prevMonth',
          [`${prefixCls}-cell-next-month`]: cell.type === 'nextMonth',
          [`${prefixCls}-cell-week-label`]: cell.type === 'weekLabel',
          [`${prefixCls}-cell-range`]: cell.range && !cell.start && !cell.end,
          [`${prefixCls}-focused`]:
            clearHours(cell.date) === clearHours(this.focusedDate),
        },
      ]
    },
  },
}
</script>
